Code No.U1109:
ETACS related CAN communication time-out
| caution |
If diagnosis code No. U1109 is set in the A/C-ECU,
diagnose the CAN main bus line.
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| caution |
Whenever the ECU is replaced, ensure that the communication
circuit is normal.
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The A/C-ECU receives air conditioner operation-related signal from the ETACS-ECU
via the CAN bus lines. If the A/C-ECU can not receive the air conditioner operation-related signal
at all on the ETACS-ECU, diagnosis code No.U1109 will be set.
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COMMENTS ON TROUBLE SYMPTOM
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Current trouble
- Connector(s) or wiring harness in the CAN bus lines between the ETACS-ECU and the
A/C-ECU, the power supply system to the ETACS-ECU, the ETACS-ECU itself, or the A/C-ECU
may be defective.
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Past trouble
- Carry out diagnosis with particular emphasis on connector(s) or wiring harness in
the CAN bus lines between the ETACS-ECU and the A/C-ECU, and the power supply system
to the ETACS-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to
GROUP 00- How to Use Troubleshooting/Inspection Service Points
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| note |
For a past trouble, you can not find it by the M.U.T.-III CAN bus diagnostics even if there
is any failure in CAN bus lines. In this case, refer to GROUP 00 - How to Cope with
Intermittent Malfunctions and check the CAN bus lines.
You can narrow down the possible cause of the trouble by referring to the diagnosis code, which
is set regarding the CAN communication-linked ECUs (Refer to GROUP 54F, Explanation about the
M.U.T.-III CAN bus diagnostics ).
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| caution |
If the ignition switch is turned to the ON position without starting
the engine, the diagnosis code U1109 (past trouble) may be set to the A/C-ECU after
three minutes.
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- Damaged harness wires and connectors
- Malfunction of ETACS-ECU
- Malfunction of the A/C-ECU
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Step 1. M.U.T.-III CAN bus
diagnostics
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 2
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 Repair the CAN bus lines. (Refer to GROUP 54F, Troubleshooting .)
On completion, go to Step 6.
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Step 2. M.U.T.-III other system diagnosis code
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Check whether the ETACS-related diagnosis code is set.
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Q.
Is the diagnosis code set?
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Diagnose the ETACS-ECU. Refer to <Except vehicles
for Hong Kong and Singapore> or <Vehicles for Hong Kong
and Singapore>.
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Go to Step 3
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Step 3. M.U.T.-III other system diagnosis code
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Check if a diagnosis code, which relates to CAN communication-linked systems below, is
set.
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- combination meter
U1109: ETACS-related time-out diagnosis code
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Q.
Is the diagnosis code set?
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Go to Step 4
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Go to Step 5
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Step 4. Check whether the diagnosis code is reset.
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Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Ignition switch: LOCK (OFF) to ON
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(3)Check if the diagnosis code is set.
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Q.
Is the diagnosis code set?
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Replace the ETACS-ECU, and then go to Step 6 .
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A poor connection, open circuit or other intermittent malfunction in the CAN bus
line between the ETACS-ECU and the A/C-ECU. (Refer to GROUP 00 - How to Cope
with Intermittent Malfunction .)
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Step 5. Check whether the diagnosis code is reset.
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Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Ignition switch: LOCK (OFF) to ON
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(3)Check if the diagnosis code is set.
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Q.
Is the diagnosis code set?
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Replace the A/C-ECU, and then go to Step 6 .
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A poor connection, open circuit or other intermittent malfunction in the CAN bus
line between the ETACS-ECU and the A/C-ECU. (Refer to GROUP 00 - How to Cope
with Intermittent Malfunction .)
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Step 6. Check whether the diagnosis code is reset.
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Recheck if the diagnosis code is set.
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(1)Erase the diagnosis code.
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(2)Ignition switch: LOCK (OFF) to ON
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(3)Check if the diagnosis code is set.
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Q.
Is the diagnosis code set?
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Return to Step 1.
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The procedure is complete.
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